autox
[Top] [All Lists]

Re: Prepared Miata reclassing thoughts

To: dave@wcsllc.net, autox@autox.team.net
Subject: Re: Prepared Miata reclassing thoughts
From: pethier@isd.net
Date: Thu, 10 Oct 2002 13:23:58 -0500
>No, I'm not joking.  I'm also not trying to start a pissing match over the
>details of Sprite suspension, it's just not that important to me.....

I'm not interested a pissing match.  If you don't understand Spridgets, that's
not a crime.

Your original contention was that nobody ever spoke of a Sprite as having poor
geometry.  My experience around Spridgets does not square with that contention.
 These are not Lotuses.  They were not designed to have good geomety.  They
were built to be cheap mass-produced cars using parts from various Austin and
Morris cars.  The fact that the have the best steering around is largely an
accident of the parts that would fit.  The roll-steer in the rear was an 
unhappier
accident of parts and their mounting.

>But, come to Nationals and poke your head under one of the faster
>Sprites.....I think you'll find lot's of parts still bolted to the factory

>locations.....

In Prepared?  Nobody is running rear coil springs?  Nobody is running coilovers
in the front instead of the lever shocks?  If this is true, where are they 
spending
their suspension money?

>and IMO Street Prepared mods such as panhard bars and coil
>overs do not count (in my mind, of course) as geometry changes...

Certainly not, and I did not mean to imply that they did.  These Street Prepared
changes are done to severely limit body roll so as to defeat the problems caused
by bad geometry by not allowing the suspension to move much.

One useful change to geometry which is allowed even in Street Prepared is to
install de-arched rear leaf springs.  The roll-oversteer inherant in the design
is caused by the angle of the front half of the leaf spring, which is 
functionally
a trailing arm.  The flatter spring does two things:  It lowers the car, which
is a Good Thing, and it makes this virtual trailing arm horizontal, removing
the geometry-caused roll-oversteer.

But I'd expect that folks spending serious money on a Prepered Class Spridget
would toss out the rear leafs altogether and hang the rear axle on a five-link
coilover setup.

(I have also seen MGB cars wherein there was a five-link setup to locate the
axle, which was then allowed ot slide on the leaf springs.  I dont' know if
anyone has ever done this to a Spridget, but it is clearly a geometry change.
 Unlike the Spridget, the MGB springs are mounted the other way, causing 
roll-understeer.
 So lowering an MGB without other changes makes matters worse.)

>.perhaps
>that comes from the changes we have to make in CP to make our '79 Fairmont

>chassis turn :)...those are geometry changes.

Don't you throw out the entire Detroit Strut and put in upper control arms?


Phil Ethier

///  unsubscribe/change address requests to majordomo@autox.team.net  or try
///  http://www.team.net/mailman/listinfo
///  Partial archives at http://www.team.net/archive


<Prev in Thread] Current Thread [Next in Thread>